Mask plate and method for exposing wafer with protrusions

Abstract

The invention provides a mask plate and method for exposing a wafer with protrusions. At least one protrusion is arranged on the side, facing the mask plate, of the wafer, a graphic layer and alignment marks are arranged on the mask plate, and notches capable of allowing the protrusions to be inserted therein are further formed in the side, facing the wafer, of the mask plate. Before the method isused for exposure, all the protrusions of the wafer are inserted into the notches corresponding to the mask plate, and the depth of the protrusions inserted into the notches is adjusted according tothe required resolution so as to keep the positions of the mask plate and the wafer unchanged after a preset exposure gap requirement is met between the mask plate and the exposure surface of the wafer, and exposing is carried out on the wafer by using an exposure light source. By utilizing the mask plate and the exposure method, a preset gap can be formed between the mask plate and the wafer exposure surface without improving a stepping photoetching machine, so that the alignment precision and the resolution ratio are improved, and the cost is saved.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to the field of photolithography, and more specifically to a mask plate and a method for exposing wafers with raised portions. Background technique [0002] The grinding process on the back of the wafer in the prior art mainly includes the Taiko process and the traditional non-Taiko (non-Taiko) grinding process. When the wafer is ground by the Taiko process, the outer edge of the wafer will be kept, and only the inside of the wafer will be ground and thinned. This process can reduce the handling risk of thin wafers, and can reduce the warpage of wafers caused by traditional grinding processes, and improve the strength of wafers. [0003] However, since the edge of the back side of the wafer processed by the Taiko process (referred to as Taiko wafer) remains, there will be a ring-shaped raised part (Taiko ring) 285-335 μm higher than the exposure surface. The engraving ...

AI Technical Summary

Problems solved by technology

[0003] However, since the edge of the back side of the wafer processed by the Taiko process (referred to as Taiko wafer) remains, there will be a ring-shaped raised part (Taiko ring) 285-335 μm higher than the exposure surface. The engraving machine cannot directly align the wafer with the convex part, and it is expensive to develop and modify, and there is also the risk of the lens hitting the ring-shaped convex, while the mask aligner (MaskAligner ) Although the back alignment of the Taiko wafer can be realized by infrared light, the existence of the ring-shaped raised portion prevents the mask plate from approaching the alignment marks on the back of the Taiko wafer, so the resolution still cannot reach the process Require

[0004] In addition, the existing Taiko wafer back exposure technology, when the gap between the mask plate and the center of the wafer is within the height range of the ring-shaped raised part, the resolution is about 30 μm, which cannot meet the requirements of the IGBT back implant photo. layer (IGBTbackside implant photo layer) process requires a high resolution of 2μm, so it is urgent to provide a mask and method for wafer exposure with bumps to meet the high resolution requirements of the Taiko wafer backside. exposure needs

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